b'related causes, including other sleep disorders,CCooggnniittiivveeffuunnccttiioonnalso increase this risk.aannddsslleeeeppddiissoorrddeerrssInsomnia is closely linked to fatigue, cognitiveImpairments in cognitive function (e.g., problems, and worse quality of life. Evaluationcognitive dysfunction) affect up to 70 percent with a sleep specialist is recommended forof people with MS, and cognitive dysfunction persistent or problematic symptoms to properlyis considered to be one of the most disabling characterize the cause and type of insomnia,symptoms of MS. Despite its prevalence and rule out other sleep-related conditions, andeffect, interventions to minimize or improve providetreatmentrecommendationsthatcognitive dysfunction in MS are limited.may include cognitive behavioral therapy.Several sleep disorders have been linked Restless legs syndrome is a condition thatto both self-reported and objective measures is associated with an uncomfortable sensationof cognitive function. In one of the rst studies in the legs, or less likely the arms, during periodsto evaluate relationships between objective of inactivity or rest, usually after prolongedsleep measures (using data from overnight sitting and during the evening hours. Thesesleep monitoring) and objective cognitive testing, symptoms, by denition, should be relieved byinvestigators from the University of Michigan voluntary movement of the limbs, even if reliefshowed that people with MS who had greater is only temporary. Restless legs syndrome issleep apnea severity performed worse on at least three times more common in peopletests that measured verbal memory, working with MS as compared to the general population,memory, processing speed, attention, and possibly because of neuroanatomical changesvisual memory. linked to MS. Low iron levels are anotherThe ndings were later observed in a larger, potential cause, not unique to MS. Otherfollow-on study. In addition to nding similar symptoms that commonly affect the legs,relationships between sleep apnea measures including spasticity and neuropathic pain, canand performance on tests that assessed mimic restless legs syndrome. An overnight sleep study is not required to diagnose restlessworking memory, processing speed, attention, legs syndrome. However, a sleep study mayand visual memory, worsening apnea severity be recommended if another sleep disorder iswas also associated with decreased cognitive also suspected that could worsen or mimicexibility, manual dexterity (hand control/ restless legs syndrome. Treatments primarilycoordination), and visuomotor coordination, include iron supplementation and medications,raising the possibility that sleep disturbances but other nonpharmacological treatmentscould affect performance across multiple including exercise also hold promise. cognitive domains in MS. 15 msfocusmagazine.org'